1. Technical Field
The present invention relates to a liquid-jet head for ejecting liquids and a liquid-jet apparatus on which the liquid-jet head is mounted. Specifically, the invention relates to an inkjet recording head for ejecting ink droplets by displacement of pressure generating means each for applying pressure to liquids respectively in pressure generating chambers communicating with corresponding nozzle orifices from which to eject ink droplets, and to an inkjet recording apparatus on which the inkjet recording head is mounted.
2. Related Art
Inkjet recording heads are mounted on inkjet recording apparatuses, including printers and plotters. Each inkjet recording head has a plurality of head main bodies each capable of ejecting an ink in the form of ink droplets. Such inks are contained respectively in ink reservoir portions in an ink cartridge, an ink tank or the like.
A general model of such an inkjet recording apparatus is capable of making color prints by ejecting ink droplets in a plurality of colors. An inkjet recording head is mounted on such an inkjet recording apparatus. The inkjet recording head has a plurality of head main bodies each for ejecting ink droplets. The plurality of head main bodies are assigned respectively to mutually different colors. Examples of this type of inkjet recording head (an inkjet recording head unit) include an inkjet recording head in which the head main bodies (inkjet recording heads) are aligned and fixed, at predetermined intervals, to a fixing plate provided near a nozzle plate. (Refer to Scope of claims, FIGS. 1 and 5, and the like in JP-A-2005-096419: hereinafter referred to as “Patent Document 1.”)
As described in Patent Document 1, for example, each head main body is configured of a passage-forming substrate, a nozzle plate, a reservoir forming plate and the like. The passage-forming substrate is formed of a single crystal silicon substrate, and is provided with pressure generating chambers and communicating portions constituting parts of each of the reservoirs. Nozzle orifices are formed in the nozzle plate, and communicate respectively with the pressure generating chambers. The reservoir forming plate includes reservoir portions and piezoelectric element holding portions. Each of the reservoir portions along with their corresponding communicating portions constitutes the reservoir. The piezoelectric element holding portion protects the piezoelectric elements.
In the case of a head main body with such a configuration, both the pressure generating chambers and parts of the reservoir are formed in the passage-forming substrate. This formation makes the area of the passage-forming substrate larger. As a result, this enlargement brings about a problem that an inkjet recording head with a plurality of head main bodies arranged side by side therein is also constructed larger. Furthermore, an interstice between each two of the head main bodies is wider. In other words, an interstice between each two rows of nozzle orifices is wider, and this accordingly makes it impossible to arrange nozzle orifices in high density. This also brings about a problem that it is difficult to enhance recording quality.
Problems of these types are common not only among inkjet recording heads for ejecting ink, but also among liquid-jet heads each for ejecting liquids other than ink.